Macrófitas aquáticas na Região Neotropical: riqueza e qualificação das espécies.

Abstract

Aquatic macrophytes are macroscopic photosynthetic organisms that encompass several taxonomic groups of plants, with broad limnological characteristics that colonize from marshes to submerged areas, playing a fundamental role in structuring wetlands and affecting aquatic biodiversity. The Neotropical Region, covering from the south of Mexico to the south of Argentina, is characterized for being one of the most biodiverse regions in the world, with a unique biota, many endemic species and a great diversity of environments. As one of the wetlands with the greatest potential in this ecozone and the world, the Paraná-Paraguay basins stand out. The objectives of this thesis were to quantify and qualify the species of aquatic macrophytes that occur in the Neotropical Region and in the Paraná-Paraguay basins, carry out an analysis of hotspots for the Paraná-Paraguay basins and provide current information and indicators of areas of high richness of aquatic macrophytes. A conservation efficiency analysis is also available that correlates areas considered hotspots and the protected areas present in these basins. Data from systematic searches in important bibliographic bases were used to compose the lists and geographic coordinates. A total of 1616 spp. for the Neotropics and 979 species for the Paraná-Paraguay basins. The families with the highest number of species were Cyperaceae Juss. and Poaceae Barnhart in both regions studied. Species richness for the Paraná-Paraguay basins was recorded using occurrence points, with 5 locations with values from 71 to 139 species and 50 locations from 1 to 11 species, with the Lower Paraná River having the lowest number of occurrences and the Lower Paraguay River the largest amount. Sixteen sub-basins considered as hotspots were registered, and these areas coincided with the areas of greatest richness. Approximately 6% of the total ecological hotspot areas are being conserved within protected areas. In conclusion, the results obtained in both surveys reaffirm the high number of species present in these wetlands, highlighting the need for further systematic and taxonomic studies of aquatic macrophytes, seeking to precisely detail these megadiverse regions.